Nonexplosive detonating fuse directional interrupter



R. L. KLoTz 3,368,485

NONEXPLOSIVE DETONTING FUSE DIRECTIONAL INTERRUPTER Feb; 13, 1968 Filed April 8, 1966 4f 422 FIG-5 4/6 4245 422@ 4/ 62y INVENTOR ROBERT-L. KLOTZ BY Z/mw, 22A/m,

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ATTORNEYS United States Patent 3,368,485 Patented Fels. 13, 1968 tice 3,368,455 NONIEXPLGSIVE DETNATING FUSE DIRECTINAL NTERRUPTER Robert L. Klotz, 16 Park Circle, Conyngham, Pa. 13219 Filed Apr. 8, 1966, Ser. No. 54l,228 11 Claims. (Cl. lin- 27) ABSTRACT F THE DSCLQSURE A nonexplosive, unidirectional, detonating wave interrupter for use with a detonating fuse comprising spacer means creating a dual sensitivity in said fuse whereby a detonating wave traveling in one direction through the fuse is continuous, and a wave traveling in the opposite direction will be interrupted. The spacer means includes means holding different portions or the fuse in spacedapart relation whereby a detonation wave traveling in one direction is transmitted through said spacing to the other portion, while a wave travelinu in the other portion, while a wave traveling in the other portion of the fuse is interrupted by the spacing between the fuse portions.

The present invention relates to detonating fuses generally and, more particularly, to a new and improved nonexplosive detonating fuse directional interrupter.

Detonating fuses are widely employed by the users of explosives in many diverse applications, including oil and gas drilling and exploratory operations, mining and excavating operations, and more recently, in the aero space industry for detonating explosive components, such as hatch bolts and the like. In many instances, it is highly desirable, for safety and operating reasons, that a detonating fuse be installed with a unidirectional interrupter whereby detonating wave travel is permitted in only one direction and is blocked out or interrupted when moving in an opposite direction.

Therefore, it is an object of the present invention to provide a new and improved detonating fuse.

M-ore specifically, it is an object of the present invention to provide a new and improved detonating fuse interrupter having a unidirectional characteristic to permit detonating wave travel in one direction only and positively interrupt or cut off a detonating wave impulse moving in the opp-osite direction.

Still another object of the invention is the provision of new and improved interrupter means for use with a conventional detonating fuse cord for interrupting a detonating wave traveling in one direction therein while permitting the travel of a wave in the opposite direction,

Yet another object of the invention is the provision of a new and improved unidirectional, nonexplosive, detonating wave interrupter which can be easily and rapidly installed in a length of conventional detonating fuse cord without requiring cutting of the fuse cord.

A further object of the invention is the provision of a new and improved unidirectional detonating wave interrupter for use with a detonating fuse which can be easily and rapidly installed in a length of fuse cord and which is completely reliable and safe in operation.

Another object of the invention is the provision of a new and improved unidirectional detonating fuse interrupter which is economical to manufacture, easy and safe to use and install, and highly reliable in operation.

These and other objects of the present invention are accomplished by the provision of a new and improved nonexplosive, unidirectional detonating fuse interrupter for preventing or interrupting the travel of a detonating wave in one direction through the fuse cord while permitting the travel of a wave in an opposite direction. The interrupter means is adapted for use with conventional types of commercial fuse cord and includes a spacer having a projectile-like shape between opposing end portions of a fuse cord adapted to transmit or permit propagation of a detonating wave traveling in one direction along the fuse cord and operable to intercept or cut off the propagation of a detonating wave traveling in an opposite direction.

In one embodiment of the invention, a tubular jacket or spaced, bent in a U-shaped conguration, is adapted to be slipped onto a continuous length of fuse cord without severing the cord, and a portion of the jacket adjacent one leg of the U is cut away to permit the cover of the fuse cord to be exposed to a segment of a cord enclosing, opposite leg of the jacket. When a detonating wave travels along the fuse cord in a direction to pass through the enclosed leg rst, fragments of the jacket from the enclosed leg are projected across the space between legs ag:inst the exposed cover of the fuse cord in the opposite leg. These fragments serve to cut or mutilate the fuse cord in advance of the traveling wave which is stopped upon later reaching the mutilated portion of the fuse cord. On the other hand, a detonating wave traveling along the cord from an opposite end toward the U-shaped spacer reaches the partially exposed leg rst and, because the opposite leg is fully protected, the fuse cord is not severed in advance of the traveling wave front. The opposite legs of the spacer are spaced apart by a distance greater than the propagation distance of the fuse cord so arranged but suciently close so that the spacer fragments can sever the cord.

In another embodiment of the invention, the fuse cord is severed to install the unidirectional interrupter, and the ends of the severed cord are inserted into opposite ends of a short, straight, tubular spacer or sleeve. The opposing ends of the severed fuse cord are held in spaced apart relation a distance greater than the normal propagation distance of the fuse cord, and a hollow projectile shaped inner spacer is interposed between the opposing ends. The projectile shaped inner spacer includes a conical projection on one end to form a cavity in the end of a fuse cord segment thereby to intensify and transmit or project the detonating wave impulse to travel across the space between the opposing fuse cord ends. The conical projection of the spacer enhances a wave traveling in one direction so that it reaches the opposing fuse cord end with suicient intensity to cause ignition thereof; however, when a wave traveling in an opposite direction reaches the other end of the hollow spacer, it is not enhanced or intensified and cannot traverse the space between fuse cord ends with suilicient intensity to initiate wave propagation in the opposite fuse cord segment and, hence, the wave is interrupted.

In other embodiments of the invention the severed fuse cord ends are inserted into opposite ends of a tubular sleeve and are held in spaced apart relation somewhat less than the normal wave propagation distance. A tubular spacer is mounted in the sleeve between opposing faces of the fuse cord segments inserted therein and the spacer is formed with valve means on one end which is opened in response to an impulse traveling in one direction to transmit the detonating wave between the fuse segments. The valve means is closable in response to a wave traveling in an opposite direction and serves to -muiile or interrupt the wave so that it will not travel across the space between the fuse segments.

Another embodiment of the invention utilizes a direct splice Ibetween severed fuse cord segments and employs spacer means which imparts a controlled bend in one segment of the fuse to enable a detonating wave traveling in another adjacent straight fuse segment to move ahead of the wave in the bent segment and sever the bent segment ahead of the wave traveling therein by detonation and fragmentations from the wave in the straight segment. This severance action is accomplished when the direction of wave travel is such as to reach the splice between the fuse segments first, before entering the bent segment, and when the detonating wave travels in an opposite direction through the bent section before reaching the splice, it passes through the spliced fuse cord without interruption.

For a better understanding of the invention, reference should be had to the following detailed description taken in conjunction with the drawings, in which:

FIG. 1 is a longitudinal cross-sectional view of one embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present invention;

FIG. 2 is a side elevational view of another embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present invention with fragmentary portions of the apparatus shown in section or partially broken away;

FIG. 3 is a side elevational view of yet another embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present invention with fragmentary portions of the apparatus in section or partially broken away;

FIG. 3a is a transverse cross-sectional view of the interrupter taken along line 3a-3a of FIG. 3;

FIG. 4 is a longitudinal cross-sectional view of still another embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present invention; and

FIG. 5 is a longitudinal cross-sectional view of a still further embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present invention.

FIG. 5a and FIG. 5b show the valve member of FIG. 5 in the open and closed positions respectively.

Referring now, more specifically, to the drawings, in FIG. 1 there is illustrated one embodiment of a unidirectional, nonexplosive, detonating fuse interrupter constructed in accordance with the present invention and indicated generally by the numeral 10. The interrupter I0 comprises a tubular outer sleeve 12 of copper or other metallic material having open outer ends adapted to receive end portions of a pair of detonating fuse cord segments 14a and 14b, which may be inserted into the sleeve in the field where the device is to be used. Generally, the fuse cord segments are cut from a continuous length of fuse cord in the field and the cut segments are then forced inwardly into opposite ends of the sleeve 12 until the square cut ends thereof abut against a pair of spaced apart annular ridges or stops 16a and leb, respectively, formed in the sleeve by a crimping operation, preferably performed at the place of manufacture and spaced apart by a distance D somewhat greater than the normal wave propagation distance of the fuse cord.

The detonating fuse cord preferably is a conventional type available commercially (for example, detonating fuse made by Ensign-Bickford Co., of Simsbury, Conn. and sold under the trade name Primacord by Du Pont & Co. and other companies) and the sleeves 1G are manufactured in suitable sizes to match the diameters or fuse cord sizes on the market. Typically, detonating fuses of this type include an inner powder core 18 encased by an outer jacket 20 of impregnated fabric, and the cornpositions of the powder core may vary widely to provide for a desired speed of detonating wave or impulse that travels along the length of the fuse when activated. For example, in a given size or diameter of detonating fuse having a core of selected composition and grain size, a detonating wave will travel along the fuse at a desired wave velocity or rate of propagation. The rate of detonating wave propagation is directly related to a functional characteristic of the detonating fuse known as the wave propagation distance, and this distance could be dened as the minimum distance or air gap between spaced facing ends of a fuse core, which would be sufficient to interrupt and stop the detonating wave travel along the fuse, once underway.

Accordingly, the distance D between the annular crimped stops or ridges 16a and 1611 in the sleeve 12 is made long enough so that the opposing, facing ends of the fuse segments 14a and Mb are spaced apart by a distance slightly greater than the propagation distance of the detonating fuse for which the interrupter 19 is designed. Consequently, a detonating wave originating in the fuse segment 14n and traveling toward the segment Mb (from left to right in FIG. l) will not be able to bridge the air gap between the spaced facing ends of the fuse cord segments, and the wave or detonating impulse will be interrupted.

In order that a detonating impulse or wave traveling in an opposite direction from the fuse segment 14a toward the segment Mb (from right to left, FIG. 1, as indicated by the arrow) will pass or carry across the air gap between the spaced, opposing end faces of the fuse segments, a hollow tubular, inner spacer 22 having a projectile-like shape is mounted in the gap or space between end faces of the fuse cord segments Ma and Mb. The spacer 22 is held in place in the sleeve 12 by the crimped annular ridges 16a and leb and, preferably, is constructed with a cylindrical body portion slightly less than the distance between the ridges. Preferably the projectile 22 is formed of metal, such as lead or copper, and includes a conically shaped closure 22a at one end thereof adjacent the end of the detonating fuse segment 14h. Because the conical closure 22a is the important functional structure of the spacer 22, the hollow cylindrical body portion thereof could be shortened or eliminated altogether. In this case, the shortened spacer or the conical projection itself could be secured in the tube 12 by another crimping ridge intermediate the ridges 16a and 1Gb. The inner spacer 22 is installed in the sleeve 12 at the factory prior to the crimping operation which produces the ridges 16a and 15b or the intermediate ridge mentioned above, and after the crimping operation, these ridges positively hold the inner spacer in the sleeve and prevent longitudinal movement thereof. Preferably, the detonating fuse is cut into the segments 14a and Mb in the eld, and the cut is made normal or perpendicular to the length of the fuse. Upon insertion of the fuse segment 14b into the sleeve 12, the sleeve is twisted as the fuse segment is inserted and the fuse segment is forced inwardly into the sleeve until the powder core ngages the conical end 22a of the inner spacer, as shown. Twisting of the sleeve during fuse insertion permits the conical end 22a to bore into the end of the powder core, as shown, and forms a concave conical recess in the core, matching that of the conical end of the inner spacer. After insertion of the fuse segment 1411 into the sleeve 12, the fuse segment 14a is inserted from an opposite end in a similar manner until it abuts the ridge 16a.

Accordingly, when the fuse segment 14b carries a traveling detonating wave moving from the right toward the conical end 22a of the inner spacer, the wave reaches the conical cavity in the powder core and the cavity produces a directionalized, high intensity jet action or Monroe effect, which is capable of bridging or carrying across the air gap between the fuse segments 14a and Mb with suiiicient concentration and intensity so that the detonation of fuse segment 14a is initiated thereby and the detonating wave continues on in a direction from right to left through the fuse segment 14a.

Thus, the interrupter lil permits and aids a detonating wave to travel therethrough when the wave is moving from the fuse segment Mb toward the segment 14a, but positively interrupts or prevents a detonating wave from traveling through the interrupter in an opposite direction because the distance between the fuse segments 14a and 14b is greater than the propagating distance or the detonating wave. The interrupter is easy to install in the field and only requires that the detonating fuse be cut andthe segments thereof be inserted into the opposite ends of the sleeve 12. After the fuse segments have been fully inserted, the sleeve is crimped in the field with a conventional crimping tool to form a pair of annular ridges 24a and 24b on the inner surface thereof to hold the fuse segments tightly in the sleeve. The interrupter is now ready for operation and is effective to positively, and nonexplosively, interrupt and terminate a detonating wave traveling through the detonating fuse in one direction while permitting such a wave to travel through the apparatus in an opposite direction.

In FIG. 2 is illustrated another embodiment of a unidirectional, nonexplosive, detonating fuse interrupter constructed in accordance with the present invention and designated generally by the reference numeral 110. The interrupter 110 is adapted for use with a continuous length of detonating fuse 114 and does not require that the detonating fuse be severed or cut into segments, as in the embodiment previously described. The interrupter includes a spacing sleeve 112 of copper or other metallic material, and the sleeve is formed into a generally U- shaped configuration, including a bight portion 112e, a pair of spaced apart, parallel side legs 1121; and 11211 and a pair of outwardly extending legs 112e, which are coaxially aligned and parallel to the bight portion 112a. The U-shaped sleeve 112 is slipped or laced onto the `detonating fuse 114 and moved along its length into the desired position. When properly positioned on the fuse in the field, a crimping tool is used to form inwardly extending annular ridges 116e and 116b on the inner surface of the sleeve legs 112e for engagement with the fuse to hold the interrupter in a selected position. The parallel legs 112 and 11211 of the sleeve are spaced apart by a distance W which is greater than the detonating wave propagation distance of the protected portion of detonating fuse 114 in the leg 112b but within mechanical damage or severance distance of the unprotected portion of the fuse in leg 1121;.

An opening or cutaway portion is provided in the leg 112b of the sleeve, as at 113, to expose an unprotected portion of the outer jacket or wrapper 20 of the detonating fuse 114, and the opening 113 is directly opposite and facing the opposite parallel protected leg 112b. Accordingly, when a detonating wave or impulse travels through the detonating fuse 114 (from right to left, FIG. 2) and moves downwardly in the leg 112b" thereof, fragments of the sleeve are ejected outwardly in a direction indicated by the dotted arrows towards the exposed portion of the cable wrapper 20 in the opening 113 formed in the opposite leg 112b. The opening 113 is substantial in length, as indicated by the letter L, to provide ample opportunity for the fragments ejected from the opposite leg 112b"y to penetrate the exposed fuse cord in the opening and mutilate or cut it, so that by the time the traveling wave or impluse moves through the fuse from the leg 112b across the bight portion 11251 of the sleeve and begins to travel upwardly in the exposed leg 112b, the fuse in the exposed leg is suiciently mutilated, cut, or severed to interrupt and stop the wave travel. On the other hand, when a detonating wave or impulse travels through the detonating fuse cord 114 in an opposite direction (i.e., from left to right), the wave reaches the exposed leg 112b rst and moves down the leg, across the bight portion 112a, and up the leg 112b" without interruption. The leg 112b" protects the fuse 114 and shields it from ejected products of detonation and fragments from the opposite leg 112b as the wave propagation proceeds downwardly therein. In addition, beca-use of the cutaway or opening 113, there are few fragments from the sleeve leg 112b available for puncturing or rupturing the opposite protected leg 112b and also, because the legs are spaced apart by a distance W greater than the wave propagation distance of the sleeve protected fuse, wave travel from left to right is not interrupted. The interrupter provides an additional advantage in that it is not necessary to cut the detonating fuse 114 in order to install the interrupted thereon. The interrupter includes only a single member, that being the sleeve 112, and no other parts or components are necessary.

In FIG. 3 is illustrated yet another embodiment of a unidirectional, nonexplosive detonating fuse constructed in accordance with the present invention and designated generally by the reference numeral 210. The interrupter 210 requires the cutting of the fuse cord into two separate segments 214:1 and 214k, which are then spliced together in the field with suitable splicing tape 215, wrapped around the body of the segment 214e some distance from the end thereof and around a portion closely adjacent the cut end of the fuse cord segment 2Mb, as shown in FIG. 3. The interrupter 21@ employs controlled bends in one of the fuse segments to effect the desired unidirectional wave interrupting characteristic and includes a straight, tubular sleeve 212 which is open at one end and can be open or closed at the opposite end, as indicated by the dotted lines 213. This tube may be serrated so as to make it more easily fragmentized by a detonating wave traveling through the fuse segment 21451. The free end of the detonating fuse cord segment 2146: is fully inserted into the sleeve 212 adjacent the opposite end thereof and is then secured in place in the field by means of a crimping tool which forms an annular, inwardly deformed retaining ridge 224.

The interrupter includes a number of outwardly extending spacing projections 221a and 221i?, preferably integrally formed with the sleeve 212 and each projection including a pair of bendable lugs 222 for holding the fuse segment 2141) in place. After the fuse segments 21451 and 21417 have been spliced together with the tape 215 and the segment 214a has been inserted into the sleeve 212 and crimped in place, the segment 2Mb is positioned along the outer ends of the projections 221:1 and 221b, as shown in FIG. 3, and the bendable lugs 222 are deformed around the fuse segment (FIG. 3a) to hold it in place in spaced relation to the sleeve 212. The projection 221a is considerably longer than the shorter projections 221b and, accordingly, the fuse segment 214th is considerably longer between the splice and the first projection 221b than is the straight fuse segment 214:1 between these two points. Accordingly, a detonating wave traveling from left to right in the straight fuse segment 214a will reach the rst projection 221]: well ahead of a corresponding separate wave traveling from the splice through the bent fuse segment 21411. The short projections 221b are dimensioned so that a distance D slightly greater than the wave propagation distance of the enclosed straight fuse segment 214a is maintained between the adjacent portions of the fuse segments 214e and 214b in the vicinity of the short projections; however, this spacing is less than the mechanical fragmentation and damage distance of the sleeve enclosed portion of the straight fuse segment 214er, so that fragments from a detonating wave therein will mutilate, sever and rupture the exposed adjacent portion of the fuse segment 214th. On the other hand, the projection 221e is substantially greater than the distance D to provide for a time lag of detonating wave traveling from the splice 215 in the fuse 214i), as previously described.

Operation of the interrupter 210 is as follows: When a detonating wave traveling in a direction from right to left (FIG. 3) reaches the splice 215, a second divergent wave is initiated in the fuse segment 2Mb. Because of the projection 221e, the wave traveling in the straight segment 214a reaches the region adjacent the short spacer projections 22M, and fragments from this wave sever the adjacent portion of the fuse segment 214]; before the divergent wave reaches the area and, accordingly, the detonating wave travel is positively interrupted. On the other hand a detonating wave traveling from right to left will pass along the fuse segment 2Mb, splice ZiS, and continue on through the segment Zilia in the same direction without interruption.

in FIG. 4 is illustrated another embodiment of a unidirectional detonating fuse interrupter constructed in accordance with the present inention, and indicated generally by the reference numeral 3ft?. in many aspects, the interrupter Si@ is similar to the interrupter it) previously described and, accordingly, corresponding parts of the interrupter 31u are numbered with reference numerals 3% higher than those of the interrupter lil. The crimped annular internal ridges Sida and 31617 in the sleeve 312 are spaced apart by a distance E somewhat less than the wave propagation distance D of the enclosed fuse segments Sida and Slt-4b. A hollow tubular valve member 322 of metal or other material is mounted in the sleeve 325.2 between the ridges 3166i and Sieb, and the member 322 is formed with a plurality of conically inwardly extending bendable valve forming segments 322.1 adjacent one end thereof. The outer tips of the segments 3:22a are normally closed together, as shown, to form a generally conical projection having a pointing coaxially toward the end fuse of the face segment 3i4a. Another annular internal ridge Side is formed at the factory in the sleeve 3M after the tubular member 2522 is inserted therein, and this ridge is adjacent the bases of the segments 322.1: and prevents longitudinal movement of the tubular valve member in the sleeve.

When a detonating wave or impulse travels from right to left (FIG. 4) through the fuse segment 31412, it reaches the end of the segment and iiows through the tubular member 322 toward the segments 32251 adjacent the end thereof. These segments are opened outwardly by the wave, permitting the wave to reach the opposite end face of the fuse segment 35i-4a. Because the opposing end faces of the fuse segments Sida and 314th are spaced apart by the distance E, which is less than the normal wave propagation distance D, the wave traveling through the valve member 322 is strong enough to penetrate and initiate detonation of the fuse segment 314er, and the wave then progresses on through the fuse segment Sit-va from right to left.

When a detonating wave or impulse travels in an opposite direction (left to right, FIG. 4) through the fuse segment Silla, the wave reaches the end face thereof and starts to move across the air gap toward the segmented conical end of the tubular valve member 322. rl`he pressure action of the wave, however, tends to force the segments 322s. into a tightly sealed conical configuration, and the wave cannot pass through the tubular member and is dissipated or interrupted by outward deflection. Accordingly, the tubular member 322 acts as a check valve to permit passage of a wave traveling from right to left to jump or traverse the nir gap E between the end faces of the fuse segments while a wave traveling in the opposite direction is interrupted by the closing or valving action of the conical segments 322:1` and becomes muffled and diverted outwardly away from the fuse segment 314b at the opposite end of the air gap. Because of the valving or muiiiing effect of the conical end segments 322a, the gap between the ends of the fuse segments 314a and 314b can be reduced somewhat below the distance D, as shown, and interruption of a wave traveling from left to right is still positively effected.

in FIG. 5 is illustrated yet another embodiment of a unidirectional, detonating fuse interrupter constructed in accordance with the present invention and indicated generally by the numeral 4314i. The interrupter 410 is almost identical with the interrupter 3i@ except for the construction of the hollow check valve member 422 therein and, hence, reference numerals with the prefix 4 will be used on parts corresponding to similar components of the interrupter 310 bearing the prefix 3.

The valve member 422 is illustrated in an open position in FIG. 5r: and in a closed position in FIG. 5b and, as illustrated in FIG. 5, is positioned in the sleeve 412 in the closed position. The valve member includes a single frapper 412e! at one end which is bendable from the closed position of FiGS. 5 and 5b to the open position of 5a during operation of the interrupter. As a detonating Wave or impulse travels along the fuse segment 414k' from right to left, it passes through the open hollow body of the valve member 422 causing the iiapper valve portion 42.2@ to open and permit the wave to reach the end face of the fuse segment al4a. Accordingly, the wave will then continue to travel along the fuse segment 414a in a direction from right to left, as indicated by the arrow. When a detonating Wave travels in the opposite direction in the fuse segment 41411 from right to left, it is interrupted or mutlied upon reaching the closed iiapper 422a which is forced thereby more tightly against the end of the hollow valve member 422.

While there have been illustrated and described various embodiments of the present invention, it will be apparent that various changes and modiiications thereof will occur to those skilled in the art. It is intended in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

l. A nonexplosive, unidirectional, detonating wave interrupter for use with a length of detonating fuse comprising structure for receiving a portion of said fuse inserted therein and including spacing means for maintaining portions of said fuse spaced apart by -a distance greater than the detonating wave propagation distance of said fuse, and nonexplosive wave enhancing means associated with said structure for intensifying and transmitting a detonating wave along said fuse across said spacing means when said wave is traveling in one direction therethrough.

2. The interrupter of claim 1 wherein said structure includes a length of tubular sleeve adapted to receive in opposite ends thereof opposing end segments of said fuse, said spacing means comprising means in said sleeve for holding said end segments inserted therein in said spaced apart relation, said wave enhancing means including a concave member inside said sleeve between the ends of said fuse segments positioned to extend inwardly into and form a cavity in the end of one of said segments, thereby producing a Monroe effect for carrying said wave across said spacing means.

3. A nonexplosive, unidirectional, detonating wave interrupter for use with a detonating fuse having la selected detonating `wave propagation distance comprising nonexplosive spacer means for creating a dual sensitivity in said fuse whereby la detonating wave traveling in one direction through said fuse is vcontinuous and a wave traveling in the opposite direction is interrupted, said spacer means including means holding different portions of saiil fuse in spaced-apart relation wherein a detonation wave traveling in one portion is transmitted across said spacing to the other portion while a wave traveling in said other portion is interrupted by said spacing between fuse portions.

4. A nonexplosive, unidirectional, detonating wave interrupter as in claim 3 for use with a continuous length of detonating fuse wherein said nonexplosive spacer means comprises a sleeve structure for encasing and bending a length of said fuse extending therethrough, said sleeve structure formed in a U-sh'aped configuration with a pair of legs having portions spaced apart by a distance slightly greater than the detonating wave propagating distance of said fuse but within the mechanical fragmentation distance thereof, one of said legs including opening defining means facing an opposite leg to expose a portion of said fuse therein to fragmentation from said opposite leg.

5. A nonexplosive, unidirectional, detonating wave interrupter as defined in claim 3` for use with spliced together segments of a fuse cord wherein said nonexplosive spacer means comprises structure for bending one of said segments in a divergent path 'away from the other whereby a wave reaching said splice initiates two separate waves traveling in each of said segments, said structure including a plurality of spacers of different length between said fuse segments, a shorter one of s'aid spacers being dirnensioned to maintain adjacent portions of said segments spaced by a distance greater than the normal wave propagation distance but less than the mechanical fragmentation distance thereof whereby the diverging one of said segments is ruptured in advance of a separate detonating wave traveling therethrough by the separate detonating wave traveling in the other fuse segment.

6. A nonexplosive, unidirectional, detonating wave interrupter as defined in claim 3 wherein said nonexplosive spacer means comprises structure for receiving a portion of one fuse segment and means for maintaining an adjacent portion of another fuse segment spaced apart by a distance greater than the detonating wave propagation distance of said fuse but less than the mechanical fragmentation distance thereof, means for splicing said fuse segments together externally of said structure, said spacing means including me'ans for bending a portion of said other fuse segment away from said one segment between said splice and said adjacent portion.

7. The fuse interrupter of claim 6 wherein said structure includes a frangible tubular sleeve for receiving a length of said one fuse segment and includes projections of different length extending outwardly of said sleeve and spaced along the length thereof for spacing said other fuse segment away from said sleeve.

8. A nonexplosive, unidirectional, detonating wave interrupter as defined in claim 3 wherein said nonexplosive spacer means comprises a tubular structure for receiving a portion of said fuse inserted therein and means for maintaining segmented end faces of said fuse in spaced apart relation in said tubular structure by a distance less than the wave propagation distance of said fuse and check valve means in said tubular structure between the end faces of said fuse segments operable to close in response to a detonating wave traveling in one direction along said fuse and operable to open in response to a wave in an opposite direction to permit passage of said wave across said spacing distance between the end faces of said fuse segments.

9. The interrupter of claim 8 wherein said check valve means includes a hollow member having valve means at one end comprising one or more movable deectors movable to close the end of said tubular member in response to a detonating wave traveling in said opposite direction and movable to open the end of said tubular member in response to the travel of said wave along said fuse in said one direction.

10. The interrupter of claim 9 wherein said deector comprises a plurality of conical segments closable together forming a conical projection extending towards the end of one fuse segment.

11. The interrupter of claim 9 wherein said deflector includes a single circular apper valve clos'able against one end of said hollow valve member.

References Cited UNITED STATES PATENTS 2,842,056 7/1958 Klotz 102-27 X 2,889,773 6/ 1959 Staadt et al 102-27 X 3,095,812 7/1963 Coursen 102-27 3,169,480 2/ 1965 SeaVy 102-27 FOREIGN PATENTS 119,465 6/ 1958 Russia.

BENJAMIN A. BORCHELT, Primary Examiner.

V. R. PENDEGRASS, Assistant Examiner. 

